compact disc com·pact·disc uncommon noun 1. a digitally encoded recording on an optical disk that is smaller than a phonograph record; played back by a laser Synonymscompact diskcompact discCD Related words Word family compact disc read-only memorycompact disc recordablecompact disc write-once Broader terms optical diskrecording Narrower terms audio CDCD-RCD-ROM WordNet 2.1 (Princeton University). WordNet 2.1 Copyright Princeton University. All rights reserved.